Question

The diameter Of a roller, 120 cm long is 84cm . if it takes 500 complete revolutions to a playground find the cost of levelling it at 75paise per square metres

Answer 1

the diameter of Roller is 84cm we know that radius is half of the diameter .
we get,
$radius \: of \: roller = 42cm$

the roller is 120 cm long that is

$height\:of\:roller \:=120cm$
CURVED SURFACE AREA OF CYLINDRICAL ROLLER
=2πrh
=2×22/7×42×120
=2×22×6×120
=31680sq.cm .

ROLLER TAKES 500 complete revolutions to level the playground

which means that its curved surface area revolves 500 times to level playground.

so,AREA OF PLAYGROUND
=500×31680
=15840000sq.cm
=158400sqm

THE COST OF LEVELLING 158400sqm area at the rate of 75 paise per sq.m

=158400×75
=11880000paise

WE KNOW THAT,
1₹=100paise

THEREFORE,
11880000/100
=118800₹

FINAL ANSWER:
THEREFORE,
THE COST OF LEVELLING THE PLAYGROUND IS ₹1,18,800

$hope \: this \: helps \: you.$